Begin by peeling the Yukon Gold potatoes. Using a mandoline or sharp knife, slice them thinly and uniformly to ensure even cooking.

Place the sliced potatoes in a bowl of cold water for about 5 minutes to remove excess starch. After soaking, drain and pat them dry with a clean kitchen towel.​

Preheat your oven to 350°F (175°C). In a large oven-safe skillet, melt 1 tablespoon of unsalted butter over medium heat.

Once melted, remove the skillet from heat and add the minced garlic, stirring to coat it evenly with the butter.​

Arrange half of the sliced potatoes in an even layer at the bottom of the skillet. Pour half of the heavy whipping cream over the potatoes, then sprinkle with half of the shredded Gruyere cheese.

Season this layer with ½ teaspoon of kosher salt, ¼ teaspoon of freshly cracked black pepper, and 1 teaspoon of fresh thyme leaves if using. Dot the layer with half of the cubed butter. Repeat the process with the remaining potatoes, cream, cheese, seasonings, and butter to create a second layer.​

Cover the skillet with aluminum foil and place it in the preheated oven. Bake for 1 hour. After this initial baking time, remove the foil and check the potatoes for tenderness by inserting a fork; they should be tender but still hold their shape.

If needed, bake for an additional 10-15 minutes. Once tender, remove the foil and continue to bake uncovered for another 15-20 minutes, or until the top develops a golden-brown crust.

After baking, remove the skillet from the oven and let the dish rest for about 10 minutes. This resting period allows the sauce to thicken slightly, making for easier serving. Spoon onto plates and enjoy this creamy, cheesy delight.​